FR2663488A1 - Method of transmitting spectrum-compatible high-definition television signals, and circuit relating thereto in a television signal transmission system - Google Patents

Abstract

An HDTV system in which the HDTV signals can have the same frequency band as those of the conventional colour television signals is disclosed. The HDTV system comprises an ITLC circuit (2) for compressing, on the basis of time, the digital information output by the A/D converter (1); a band separation circuit (3) for separating the signal output by the ITLC circuit (2) into low- and high-frequency bands; a movement vector detector (4); a high-frequency band signal processor (5) for processing the high-frequency band signals coming from the band separation circuit (3) on the basis of the movement vector signals from the movement vector detector (4); a first LPF (12) for filtering the high-frequency analog signal, a second LPF (13) for filtering the low-frequency analog signal and a quadrature modulator (14) for producing a transmission signal from the latter.

Description

TELEVISION SIGNAL TRANSMISSION METHOD
HIGH DEFINITION SPECA-COMPATIBLE
AND RELATED CIRCUIT IN A TRANSMISSION SYSTEM
TELEVISION SIGNALS
The present invention relates to a method and a circuit for transmitting spectrum compatible high definition television signals in a television signal transmission system, in which a frequency band separation technique and a subsampling technique are used.

Since the 1960s a high television system (HDTV) has been developed in Japan. Different prototypes of HDTV systems have been proposed, such as the Japanese MUSE system (coding for multiple sub-sampling below the Nyquist rate), the system
European HD-MAC, the spectrum compatible HDTV system
Zenith DSRC AC-TV, the MIT system using a sub-frequency band coding technique and the SLSC from Bell Laboratory developed by the USA However, one of the problems to be solved is to make an HDTV system compatible with a system On this point, the Japanese MUSE system is incompatible with a conventional color TV system, while the HDTV system of AC-TV is compatible with a conventional NTSC (National Television Systhem Committee) color TV but it has considerable obstacles to overcome, one of which is the extension of the frequency band to the desired level.

It is an object of the present invention to create an HDTV system in which the HDTV signals can have the same frequency band as that of the broadcast signals.
Conventional color TV and can be transmitted via an unoccupied channel of the conventional color TV system.

 Another object of the present invention is to provide an HDTV system designed to be compatible with the conventional TV signal transmission system and which uses the frequency band separation technique together with the subsampling technique.

To this end, the present invention provides a circuit for transmitting spectrum-compatible high definition TV signals in a TV signal transmission system. Comprising an analog-to-digital converter (A / D converter) for converting a luminance signal and chrominance signals into digital data; a time compressed luminance and chrominance signal integration circuit (ITLC) for compressing on the basis of time the digital information output from the A / D converter; a band separation circuit for separating the signal output from the ITLC circuit into low and high frequency bands; a motion vector detector for detecting the motion vector from the low frequency band signals of the band separation circuit; a high frequency band signal processor for processing the high frequency band signals from the band separation circuit based on the motion vector signals of the motion vector detector; a delay circuit for delaying low frequency band signals from the band separation circuit; a command and synchronization adder for adding the output of the delay circuit to the motion vector signal of the motion vector detector; an audio encoder for encoding audio signals inputted through an audio input terminal; an audio and synchronization adder for adding the signals output from the audio encoder to the signals output from the high frequency band signal processor; a first digital-to-analog converter (D / A converter) for converting the signals output from the audio and synchronization adder; a second D / A converter for converting the signals output from the command and synchronization adder; a first low pass filter (LPF) for filtering the signals output from the first D / A converter; a second low pass filter to filter the signals from the second converter
D / A; a quadrature modulator for multiplying the signals output from the first and second low pass filters by a Cosot signal and a Sinot signal, respectively, and then for synthesizing the multiplied signals with each other to produce a signal from there transmission; and a transmission processor for processing the transmission signal so that it is adapted to be transmitted.

The characteristics and advantages of the invention will become apparent from the description which follows by way of example with reference to the accompanying drawings, in which
Figure 1 is a block diagram to represent the circuit of the invention;
Figure 2 is a block diagram for showing the high frequency band signal processor 5 of Figure 1;
Figure 3 shows a signal composition of ITLC 2 of Figure 1;
FIG. 4 is an example of frequency band separation of the frequency band separation circuit 3 of FIG. 1;
FIG. 5 is an example of a motion vector in a screen;
Figure 6 shows the characteristic graphs of the signal offsets of the frequency offset circuit 52 of Figure 2;
FIG. 7 represents the output characteristics of an HVT filter 54 of FIG. 2 ;;
Figure 8 shows the sampling structure of the frame shift subsampling circuit 56 of Figure 2;
FIG. 9 shows a spectrum structure according to the conversion in a proportion of two to one of the first and second sampling circuits 58, 59 of FIG. 2;
Figure 10 shows a sampling structure of the first and second field shift subsampling circuits 61, 62 of Figure 2;
FIG. 11 represents the characteristics of the low pass filter HV 53 of FIG. 2 and of spectrum folding;
FIG. 12 shows a detection of a movement zone; and
FIG. 13 represents a spectrum of a transmission signal.

 Referring to Figure 1, an analog-to-digital converter (A / D converter) 1 is used to convert a luminance signal Y and chrominance signals R-Y and B-Y into digital data. A time compressed luminance and chrominance signal integration circuit (ITLC) 2 is used to compress on the basis of time the digital information output from the A / D converter 1. A band separation circuit 3 is used to separate the ITLC 2 circuit output signal in low and high frequency bands.

 A motion vector detector 4 is used to detect a motion vector from the low frequency band signals of the band separation circuit 3. A high frequency band signal processor 5 is used to process the high frequency band signals from of the band separation circuit 3 as a function of the motion vector signals of the motion vector detector 4.

A delay circuit 6 serves to delay the low frequency band signals from the band separation circuit 3.

 A command and synchronization adder 8 adds the output of the delay circuit 6 to the output of the motion vector signal from the motion vector detector 4. An audio coder 9 codes audio signals input via a terminal d audio input (AI). An audio and synchronization adder 7 adds the signals output from the audio encoder 9 to the output of the high frequency band signal processor 5.

 A first D / A converter 10 converts the signals output from the audio and synchronization adder 7.

A second D / A converter 11 converts the signals output from the control and synchronization adder 8. A first low pass filter 12 filters the signals output from the first D / A converter 10. A second low pass filter 13 filters the output signals of the second D / A converter 11.

 A quadrature modulator 14 multiplies the signals output from the first and second low pass filters 12, 13, respectively, by a Cosot signal and an Otherwise signal, and then it adds the multiplied signals to each other to produce from these a transmission signal. A transmission processor 15 processes the signals output from the quadrature modulator 14, so that they are suitable for transmission.

 Referring to Figure 2, the high frequency band signal processor 5 includes a frequency shift circuit 52, a low pass HV (horizontal-vertical) filter 53, an HVT (horizontal-vertical-time) filter 54 , a frame shift subsampling circuit 56, a low pass filter 57 a second sampling circuit 59, a T (time) filter 60, a second field shift subsampling circuit 62, a zone detection detector movement 55, a first sampling circuit 58, a first field shift subsampling circuit 61, and a mixer 63.

 The frequency shift circuit 52 is used to shift the high frequency band signals from the band separation circuit 3, a low-pass filter H-V 53 is used to filter the output signals of the frequency shift circuit 52 horizontally and vertically.

 An H-V-T filter 54 is used to filter the signal output from the frequency shift circuit 52 in the horizontal, vertical and time directions. A frame shift subsampling circuit 56 serves to sub-sample the output signal of the H-V-T filter 54 in frame shift.

 A low pass filter 57 is used to filter the output signals from the frame shift subsampling circuit 56 in the horizontal direction.

 A second sampling circuit 59 is used to sample the output signals of the low pass filter 57 in the proportion of two to one. A T filter 60 is used to filter the signals output from the second sampling circuit 59 along the time axis, a field shift subsampling circuit 62 is used to sub-sample the output signals of the T filter 60 in field shift . A movement area detector 55 is used to detect a movement area by receiving the output signals of the low-pass filter H-V 53 as a function of the output signals of the movement detector 4.

A first sampling circuit 58 is used to sample the output signals of the low pass filter
HV 53 in the proportion of two to one. A first field shift subsampling circuit 61 is used to sub-sample the output signals of the first sampling circuit 58 in field shift. A mixer 63 is used to mix the output signals of the first field shift subsampling circuit 61 with the output signals of the field shift subsampling circuit 62, as a function of the signals output from the motion area detector 55.

 Figure 4A shows the full band of ITLC 2 output signals, Figure 4B shows the separation in the low frequency band, and Figure 4C the separation in the high frequency band.

 The characteristics before and after the frequency shift are respectively shown in FIGS. 6A and 6B. The characteristics of the H-V-T filter 54 of FIG. 2 are shown in FIGS. 7A and 7B respectively representing the filtering in the directions of the vertical axis and the time axis.

 The spectrum structures according to the conversion in the proportion of two on one of the first and second sampling circuits 58, 59 of FIG. 2, are shown in FIGS. 9A and 9B representing them respectively before and after the sampling conversion.

 The characteristics of the H-V filter are shown in FIG. 11A, and the folding spectrum of the field shift sub-sampling of the dynamic zone signal processing channel is represented in FIG. 11B.

 A preferred embodiment of the present invention will now be described with reference to FIGS. 1 to 13.

The output signals of a video camera are entered as Y, RY, BY signals in the A / D converter 1. The signal band of Y is 22.5 MHz and those of Ry and
BY are 7.5 MHz. The digital signals from the A / D converters 1 are compressed in time to be rearranged as shown in FIG. 3 by the ITLC circuit 2.

 Referring to Figure 3, the chrominance signal is compressed in the proportion of four to one, and the luminance signal in the proportion of four to three, whereby a quarter of the signal line is occupied by the signal chrominance, and the remaining three quarters by the luminance signal. In addition, the chrominance signals consist of R-Y and B-Y arranged alternately.

In the present embodiment, the even fields and the odd fields are combined to form a frame.

In which the chrominance signals are arranged in the successive order of: even field R-Y, odd field R-Y, even field B-Y and odd field B-Y.

 The output signals of the ITLC circuit 2 are separated into a low frequency band signal and a high frequency band signal by the band separation circuit 3. In this case, if the band of the input signal is Xo, the signals in the frequency band from 0 to Xo / 5 are output as the low frequency signal and the signals in the frequency band from Xo / 5 to Xo as the high frequency signal. Namely, in the case of the luminance signal, the signals in the frequency band from 0 to 4.5 MHz are output as the low frequency band signal, and the signals in the frequency band from 4.5 to 22.5 MHz as a high frequency band signal.

In this way, in the case of the chrominance signal, the signals in the frequency band from 0 to 1.5 MHz are output as a signal from the low frequency band, and the signals in the frequency band from 1, 5 to 7.5 MHz as a signal of the high frequency band.

 The signal of the low frequency band of the band separation circuit 3 is used for the motion vector detector 4 to detect the amplitude of the motion.

Namely, the motion vector detector 4 produces a vector amplitude corresponding to the value of the transverse expansion or the interference of the whole screen, as shown in FIG. 5.

By a displacement of AX in the direction X and of AY in the direction Y, the signal takes the vector value of AY and AX as in figure 5. Naturally, the vector value consists of binary numbers, in which each direction has four bits and the horizontal value is 4MSB (most significant bits). Namely, the vector value is (Xs, X2, X1, Xa, YSt Y2,
Y1, Ya) in which Xs, Ys are bit symbols.

 The motion vector produced from the motion vector detector 4 and the low frequency band signal applied via the delay circuit 6 are simultaneously supplied to the control and synchronization adder 8 so as to synchronize the two signals.

 The control and synchronization adder 8 receives the motion vector and synchronization information together with other information.

In this case, the vertical synchronization information is entered at the start of the field and the horizontal information at the start of each line. The motion vector information is entered in the vertical spot return interval, not in the scan line.

Assuming the scan lines are 1,080 in 1,250 lines, free space is found for 170 lines per frame or 85 lines per field, in which an appropriate line is selected to enter the motion vector information. Other information such as teletext information, etc.

can be transmitted through free spaces.

 The signal of the high frequency band of the band separation circuit 3 is supplied to the signal processor of the high frequency band 5, the signal processing of which is shown in FIG. 2. The high frequency band signal is supplied to the frequency shift circuit 52 so that it is offset from the filtered low frequency as shown in Figure 6. That is, the high frequency band signal is moved from the frequency band of Xo / 5 so as to modify the frequency band from Xo / 5 to Xo into the frequency band from 0 to 4Xo / 5. This shifted high frequency band signal is processed through two channels, one of which is the dynamic zone signal processing channel, and the other is the static zone signal processing channel. signal processing channels the two pieces of information are appropriately proportioned so that they are output according to the degree of movement.

The static and dynamic signal processing channels pass respectively through the HVT filter 54 and the low pass filter HV 53. The output of the frequency shift circuit 52 is applied to the filter.
HVT 54 whose characteristics are shown in Figure 7. The HV filter (horizontal and vertical filter) passes the region of Y <Yo and X <4Xo / 5 as shown in Figure 7A, and the HT filter (filter horizontal and temporal) passes the region of Z <Zo / 4 and X <4 / 5Xo as shown in Figure 7B where Yo is the number of TV lines, Zo is the frame frequency and Xo the maximum band frequency video signal (i.e.
Yo = 1,250 TV lines or 1,080 scan lines, Zo = 7.5 MHz, Xo = 22.5 MHz).

The output of the HVT filter 54 is sampled by the frame shift subsampling circuit 56 as shown in FIG. 8. The sampling frequency of X'o is 4Xo / 5, and the sampling frequency of the signal of 2X'o origin, thus, a folding spectrum appears which is observed in the HV direction but not in the TV direction. The bandwidth of
X'o / 2 in the direction of the time axis in FIG. 7B serves to prevent the spectrum from folding back.

 The output of the frame shift subsampling circuit 56 is applied to the low pass filter 53.

The horizontal LPF 57 has a bandwidth of X'o / 2. The sampling frequency again becomes 2X'o after passing through the low pass filter 57. Referring to FIG. 9A showing the structure of the spectrum passing through the low pass filter 57, the frequency band going from X ' o / 2 to X'o is folded in the frequency band going from 0 to X'o / 2.

 The output of the low pass filter 57 passes through the second sampling circuit 59, so the sampling frequency is changed from 2X'o to X'o. In the spectrum, the signal having the spectrum structure of Figure 9A becomes the signal with the spectrum structure of Figure 9B. Namely, the signal distributed around the frequency 2mX'o becomes the spectrum developed around mX'o, as shown in FIG. 9A (m is an integer).

 The output of the second sampling circuit 59 is supplied to the filter T 60 (filter in the direction of the time axis) which is a pre-filter to prevent blurring during the sampling of the field shift subsampling circuit 62, this filter only passes the signal going from 0 to 15 MHz.

 The signal having passed through the filter T 60 is sampled by the field shift sub-sampling circuit 62 as shown in FIG. 10, in which the sampling frequency is X'o / 2.

Another folding of the spectrum occurs. Thus, in the frequency spectrum, the signal going from X'o / 4 to X'o / 2 is again folded over the signal going from 0 to X'o / 4 of the signal folded back from the frame shift subsampling in the horizontal-vertical directions. In the spectrum
HT the signal is introduced inside the spectrum between 15 MHz and 30 MHz in the direction T. Namely, the folding of the spectrum is obtained without blurring.

By adding the spectrum folding processing from the HVT filter 54 of the static area processing channel of the field shift subsampling circuit 62, the signal passing through the HVT filter 54 is folded in the frequency band going from X ' o / 2 at X'o with the range 7.5 to 15 MHz in the direction of the time axis by the frame shift subsampling circuit 56, while the signal passing through the filter T 60 is folded in the frequency band from X'o / 4 to X'o / 2 within the range of 15 to 30
Hz by the field shift subsampling circuit 62.

The output of the frequency shift circuit 52 is also applied to the low pass filter HV 53 of the dynamic zone processing channel. The HV 53 low pass filter only passes the frequency band from 0 to
X'o / 2 of the band signal X'o entered in the horizontal low pass filter with a frequency band of X'o / 2 and the frequency band going from 0 to Yo / 2 of the band signal Yo entered in the vertical low pass filter with a frequency band of Yo / 2. The above signal is delivered to the first sampling circuit 58. This signal is not aliased.

The sampling frequency passing through the first sampling circuit 58 is changed from 2X'o to X'o. The signal passing through the first sampling circuit 58 is applied to the first field shift subsampling circuit 61 and sampled in the sampling structure as shown in FIG. 10. In this case, the sampling frequency is X 'o / 2 and the frequency band from X'o / 4 to X'o / 2 is spectrally folded over the frequency band from 0 to X'o / 4. The folded signal of the frequency band from X'o / 4 to X'o / 2 is introduced vertically between
Yo / 2 and Yo.

 The characteristics of the low-pass filter H-V 53 are shown in FIG. 11A, and the folding of the spectrum of the first field shift subsampling circuit 61 in FIG. 11B. The output of the HV low pass filter 53 is supplied to the motion area detector 55 which detects the motion area by both the motion vector and the output of the HV low pass filter 53. The motion area detector 55 shifts the screen enlarged transversely and blurred by the motion vector to the value of AX and AY, as shown in Figure 5.

This compensates for the transverse enlargement and the scrambling of the screen in order to capture each of the partial movements.

For the rest, all the parts are represented as the dynamic zone. In practice, in the case of transverse enlargement and interference of the above transmission system, the signals are treated as the static area after detection of the motion vector. Referring to FIG. 12, the part hatched by lines in the part where the movement occurs is detected as being the movement zone by comparing the (n + l) th field with the (n + 3) th field in which the screen offset caused by the transverse enlargement and the interference is compensated by the motion vector. The signals output are divided into different levels according to the amplitude of movement of the movement zone. The output of the movement zone detector 55 is entered into the mixer 63 which mixes the outputs of the processing channels of the dynamic and static zones according to the output signal of the motion zone detector 55.

The signal output S of the mixer 63 is a function of the output of the motion zone detector 55 according to the following equation
S = k Sm + (1 - k) Ss
In which Sm is the output signal of the first field shift subsampling circuit 61, SS the output signal of the second field shift subsampling circuit 62 and k the amplitude of movement of the zone detector output movement 55.

 The output of the mixer 63 is entered into the audio and synchronization adder 7 of FIG. 1 which also receives the audio signal and the synchronization information. The audio and synchronization information to the audio and synchronization adder 7 is as follows.

 The vertical synchronization information is entered at the start of each field, and the horizontal synchronization information at the start of each line.

Audio information is input during the vertical spot return interval, not during the scan line.

Assuming the scan lines are 1,080 in 1,250 lines, free spaces are produced of 170 lines per frame or 85 lines per field, in which an appropriate line is selected to enter the audio information.

The output of the audio and synchronization adder 7 is applied, via the first D / A converter 10, to the first low pass filter 12 having a frequency band of X'o / 4 relative to the horizontal axis. In the same way, the output of the command and synchronization adder 8 is applied via the second D / A converter 11 to the second low pass filter 13 having a frequency band of X'o / 4 relative to the horizontal axis. The signals from the first and second low pass filters 12 and 13 are modulated in quadrature and phase respectively. Assuming that the output of the second low pass filter 13 is VL, the output of the first low pass filter 12 is VH, and the frequency modulated intermediate 01 = 27r fl, the output of adder A modulated in phase quadrature is as follows
Adder output = aVL Sinx1t + BVH Cosolt
In which a and B represent the gains of VL and VH respectively. The gain a is greater than the gain B.

The output of the quadrature modulator 14 is transmitted through the transmission processor 15. The output signal is processed through the filter as shown in Figure 13. This filter has a lower frequency band of X and a higher frequency band of X'o / 4 compared to the frequency fs of the RF carrier (radio frequency), in which X is equal or less than (1/4) X'o / 4. The reason why the signal with the frequency band as shown in figure 13 is transmitted is to equalize the upper band and the lower band so as to extract, from the signal received via the intermediate carrier signal, the signals VH and VL in phase and in phase quadrature. Otherwise there would be a phase shift.

 Then the signal passes through the low pass filter whose lower or upper frequency bands are smaller than X with respect to fs, thereby equalizing the upper and lower frequency bands. By this means, if a Nyquist filter is used as in the NTSC system, a reversing Nyquist filter must also be used on the reception side.

As described above, the HDTV transmission system of the present invention uses both the subsampling technique and the band separation technique, the signal processing varies considerably with the undersampling and separation of bands for each signal, in each position and in each step. For example, MUSE and HD-MAC use the subsampling technique and MIT and
Zenith, etc. the subband coding technique or the band separation technique.

Thus, the present invention provides a system for
HDTV in which the signals have the same frequency band as that of conventional color TV signals and are transmitted via an available channel of the conventional color TV system. The HDTV system is compatible with the conventional color TV signal transmission system and uses a frequency band separation technique along with a subsampling technique.

Claims (4)

 1. A circuit for transmission of spectrum-compatible high definition television signals in a television signal transmission system, said circuit comprising  an analog-to-digital converter (1) for converting a luminance signal (Y) and analog chrominance signals (R-Y, B-Y) to digital data;  means (2) for integrating luminance (Y) and chrominance (R-Y, B-Y) signals compressed in time (ITLC) to compress on the basis of time said digital signal;  band separation means (3) for separating the signal output from said integration means (2) into low and high frequency band signals respectively;  motion vector detection means (4) for detecting the motion vector of the low frequency band signal of said band separation means (3);  high frequency processing means (5) for processing the high frequency band signal from said band separation means (3) in accordance with the motion vector signal from said motion vector detection means (4);  delay means (6) for delaying the low frequency band signal from said band separation means (3);  first synchronization means (8) adding the signal output from said delay means (6) to the motion vector signal from said motion vector detection means (4);  audio coding means (9) for coding the audio signal inputted through an audio input terminal;  second synchronization means (7) for adding the signal output from said audio coder (9) to the signal output from said high frequency band processing means (5);  a first digital-to-analog converter (10) for converting the signal output from said second synchronization means (7);  a second digital-to-analog converter (11) for converting the signal output from said first synchronization means (8);  a first low pass filter (12) for filtering the signal output from said first digital-to-analog converter (10);  a second low pass filter (13) for filtering the signal output from said second digital-to-analog converter (11);  quadrature modulation means (14) for multiplying the outputs of said first and second low pass filters to give sinusoidal signals, respectively, and then for synthesizing the multiplied signals with each other to produce therefrom a transmission signal; and  transmission means (15) for processing said transmission signal according to given transmission criteria.  2. Circuit for transmission of spectrum compatible high definition television signals in a television signal transmission system, as claimed in claim 1, characterized in that said means for processing the high frequency band (5) comprises  shift means (52) for shifting the signals of the high frequency band from said band separation means (3);  a first low pass filter (53) for filtering the signal output from said shift means (52) horizontally and vertically;  a first filter (54) for filtering the output signal from said shift means (52) in the horizontal and vertical directions and the time axis;  first sub-sampling means (56) for sub-sampling the signal output from said first filter (54) in frame shift;  a second low pass filter (57) for filtering the output signal from said first subsampling means (56) in the direction of the horizontal axis;  first sampling means (59) for sampling the output signal of said second low pass filter (57) in the proportion of two to one;  a second filter (60) for filtering the output signal from said first sampling circuit in the direction of the time axis;  second subsampling means (62) for subsampling the signal output from said second filter (60) in field offset;  motion area detection means (55) for detecting a motion area by receiving the signal output from said first low pass filter (53) based on the signal output from said motion vector detection means (4);  second sampling means (58) for sampling the output signal of said first low pass filter (53) in the proportion of two to one;  third subsampling means (61) for subsampling the signal output from said second sampling means (58) in field offset; and  a mixer (63) for mixing the signals output from said second subsampling means (62) and the signals output from said third subsampling means (61), based on the signal output from said motion area detection means (55).  3. A method of transmitting spectrum compatible high definition television signals in a television signal transmission system, comprising the steps of  separating the luminance (Y) and chrominance (B-Y, R-Y) signals converted into digital signals into a low frequency band signal and a high frequency band signal, said digital signals being compressed over time;  detecting a motion vector from the separated low frequency band signal;  processing said high frequency band signal as a function of the values of said motion vector;  conversion of said separate low frequency band signal into a first analog signal by means of low pass filtering, said separate low frequency band signal being delayed by a determined duration and added to said motion vector;  converting the processed high frequency band signal added to an audio signal into a second analog signal via second low pass filtering; and  multiplying the outputs of said first and second low pass filtered signals by given sinusoidal signals, respectively, and then synthesizing the multiplied signals with each other to produce a transmission signal therefrom.  4. A method of transmitting spectrum compatible high definition television signals in a television signal transmission system, as claimed in claim 3, characterized in that said step of processing said high frequency band signal further comprises the stages of  shifting said separate high frequency band signal;  performing a third low pass filter for the signal shifted in the directions of the horizontal and vertical axes, and a fourth low pass filtering for said signal shifted in the directions of the horizontal, vertical and time axes;  detection of a movement area by reception of said third filtered low pass signal as a function of the values of said movement vector; ;  execution of a first sub-sampling in frame for said fourth filtered signal, said first sub-sampled signal being subjected to a fifth low-pass filtering;  sampling and filtering along the time axis of said fifth filtered low pass signal, the sampled signal is filtered being subjected to a second subsampling in field shift;  sampling said third low pass filtered signal, the sampled signal being subjected to a third field shift sampling; and  mixing said second undersampled output signal and said third undersampled output signal as a function of said value of the motion area.